Surgical instruments use a variety of methods to control the operating speed of the instrument. For example, a powered surgical instrument may use a control lever that can be moved to increase or decrease the operating speed of the instrument. In other examples, a foot pedal may be used to increase or decrease the operating speed of the surgical instrument.
Some conventional powered surgical instruments include the control lever fixed to the instrument. The control lever may be resiliently and pivotally coupled to the instrument such that a user may pivot the control lever towards the instrument to increase the operating speed, and then allow the control lever to resiliently pivot away from the instrument to decrease the operating speed. The control lever may provide only limited adjustability of finger control positions for the surgeon, mostly predefined positions and not cover all ergonomic positions for ease of use and access to the surgical site. Some conventional powered surgical instruments include sensors positioned close to the perimeter of the housing and aligned with the housing to detect a magnetic field perpendicular to the housing to detect movement of the control lever in order to increase, decrease, or maintain the operating speed of the surgical instrument. Typically four sensors are disposed in the housing in order to detect the magnetic field when the control lever is positioned in one of the predefined positions. Alignment of the sensors within the housing in order to detect the perpendicular magnetic field of the magnet in the control lever can be difficult. The size of the surgical instrument must be large enough to accommodate all of the sensors in their aligned positions.